problem in amavis + spamassasin

PartnerNOC

Acutually, my admin considers how to embed spamassasin into amavis. However, the following loop has been made if the comment-outs are removed.
In fact, exim is regarded as a outer command by amavis.
Anybody knows how to avoid any loop in the combination of amavis and spamassasin. Thanks.